Laure Beccuau said the DNA of a 37-year-old man who was charged on Saturday was found inside the basket lift that was used to reach the museum's window.
He was handed preliminary charges of theft by an organised gang and criminal conspiracy.
His criminal record contained 11 previous convictions, 10 of them for theft, Beccuau said.
The criminal record of a 39-year-old suspect who was handed similar preliminary charges on Wednesday mentions 15 convictions including two for theft, Beccuau said.
"What's interesting about these records, when we compare them, is that … we see that they were both involved in the same theft case, for which they were convicted in Paris in 2015," Beccuau said.
Another man aged 34 suspected of being part of the "commando" team, as French media have dubbed the thieves, was also charged this week.
A 38-year-old woman who was handed preliminary charges of "complicity" on Saturday is the longtime partner of the 37-year-old suspect, Beccuau said, noting some "closeness" between all suspects.
All four are being held in custody.
Beccuau declined to answer a question about whether investigators are getting closer to finding the jewels.
"We are examining all the possibilities on the parallel market for selling this jewellery, which I hope will not happen anytime soon ... It could be used for money laundering, it could be used for trade, all leads are being explored," she said.
Interior Minister Laurent Nuñez said he remains "optimistic" about the investigation, in an interview with Le Parisien newspaper on Saturday.
"There are four perpetrators, at least one of whom remains at large, plus possibly the one or those who ordered the crime and the jewellery," Nuñez said.
"I have great confidence in the work of the police, so I'm optimistic. But my optimism doesn't extend to thinking that the loot will be recovered quickly," he added.
